Question: Simplify the following expression: ${3(-n+4)-3(1-3n)}$
Solution: Distribute the ${3}$ into the first set of parentheses: $ {3(}\gray{-n+4}{)} - 3(1-3n) $ $ {-3n+12} - 3(1-3n) $ Distribute the ${-3}$ into the parentheses: $ -3n+12 {-3(}\gray{1-3n}{)} $ $ -3n+12 {-3+9n} $ Rewrite the expression to group the ${n}$ terms and numeric terms: $ {-3n + 9n} + {12 - 3}$ Combine the ${n}$ terms: $ {6n} + {12 - 3}$ Combine the numeric terms: $ {6n} + {9}$ The simplified expression is $6n+9$